1. Field of the Invention
The present invention relates to an apparatus and method for three dimensional (3-D) modeling and to a 3-D modeling program.
2. Description of the Related Art
In recent years, computer graphics have been used in various fields and consequently, 3-D graphics images are in wide use. In order to create a 3-D graphics image, 3-D model data which consists of shape and texture is required. However, because such data is too enormous in size to create manually, it is desired to make obtaining 3-D model more efficient.
To this end, various 3-D scanners are being developed for inputting into a computer the shape and texture (color and pattern) of a 3-D target object.
For instance, Japanese Patent Laid-Open Publication No. 2001-108421 discloses a 3-D modeling apparatus in which a series of images of a target object on a turntable to which marks for detecting position are attached are captured by a camera, in each captured image the camera position is obtained based on the marks attached to the turntable and a silhouette is extracted, and 3-D model data is produced based on the position and silhouette information.
By using such a 3-D modeling apparatus, it is possible to obtain 3-D graphics data of a target object, and it is thus possible to reduce the amount of work for initial input to substantially zero.
However, in the apparatus disclosed in Japanese Patent Laid-Open Publication No. 2001-108421, the overall target object and the turntable must always fit in the captured image. Therefore, when the target object is large, the camera must be moved away from the target object, thus causing degradation in the precision of the shape and the fineness of the texture. There is also a problem in that a broad space is required for capturing images.
The present invention is conceived to solve the above problem and an object of the present invention is to provide an apparatus and method for 3-D modeling which are easy and cost less, and which can accommodate a larger target object. Another object of the present invention is to provide a medium onto which the 3-D modeling program is recorded.
According to an aspect of the present invention, a plurality of cameras are used. Because a plurality of cameras are used, it is possible to capture images of the entirety of a relatively large target object at a close distance. Therefore, modeling with highly precise acquisition of shape and texture can be performed using a compact apparatus and the cost for the apparatus can be reduced. In addition, because the calibration among the plurality of cameras can be performed based on captured images of a reference object designed to detect camera position, precise adjustment of the positions of cameras is not required, thus allowing for easier operations.
According to another aspect of the present invention, it is preferable that the plurality of cameras be placed at positions separated from each other in the vertical direction. With such a configuration, the entirety of a vertically elongated target such as a person can be easily captured.
According to yet another aspect of the present invention, it is preferable that a plurality of cameras be synchronized while the turntable is continuously rotated.
By employing a continuous rotation, it is possible to reduce change in the angular acceleration and to effectively prevent the target object such as a person from moving during the rotation.
According to another aspect of the present invention, it is preferable that a voting process be applied separately to the images captured by each camera to generate voxel data and that the voxel data are then synthesized. In this manner, a voting process identical to that used for a case of one camera can be employed, and a 3-D modeling process can be performed by a simple method of, for example, taking the logical sum of the obtained voxel data.
According to another aspect of the present invention, it is preferable that the captured images from each camera be synthesized based on the relative viewing position of each camera and a voting process be applied to the synthesized data to generate voxel data. With such a configuration, the entirety of the target must be captured only in the data after the synthesis, and therefore, the degree of freedom for placing the cameras can be improved.
The present invention also relates to a method for 3-D modeling using the apparatus as described above or a program which uses such a method.